Electric safety-lamp.



E. GOTTSGHALGK, L. WERNER &. A. GAST.

ELECTRIC SAFETY LAMP.

APPLICATION FILED DEO.7,1912.

Patel l ted Oct. 21,1913.

2 SHEETS-*SHEET 1.

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' E. GOTTSOHALOK, L. WERNER & A. GAST.

ELEGTRIG SAFETY LAMP.

APPLICATION FILED D130. 7, 1912.

Patented 001;. 21, 1913.

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K 8 IH I M 1 G C n m J "NEW x UWZ/J I 1m ills-JP r s1 GOTTSGHALCE, AUGUST G FABRIK.

TREPTOW, NEAR BERLITT, VJERNER, 03F BERLIN, AND "1ST, Ell? STEGIEITZ, GERMANY, ASSIGNORS. "J30 THE FIRM 0F GHEMISGHE IESIKEIIVE-ELEKTRQN, OF FRANKFORT-GIT-THE-MAIN, GFLERIJJHLNY.

snno'rnic shanty-Lance.

Specification of Letters Eatent. Pwtgmfggfl 21 19133,,

Application filed December 7, 1912. Serial No. 235,421.

1/ b all 712710 172 ii 172 ay concern Be it known that we, Rain. GOTTSCIIALCK, I, a resident of Treptow, near Berlin, Lori-inn WERNER, a resident of Berlin, and linens: GASL, aresident of Steglitz, near Berlin, Germany, citizens of Germany, have invent? ed certain new and useful Improvements in Electric Safety-Lamps, of which the following is a specification.

Our invention relates to an electric lamp which canbe made in portable form or as a stationary lamp and which is so constructed that it. can be used without danger in mines,- in various industrial factories, and so on where combustible gases may exist. In such cases, as is well known, care must be taken that the gasesare not ignited by sparks, whether through actions in contravention of regulations, through accidents to the lamps, or through malicious dealings.

The subject of the invention belongs to a class of lamps, of which several types are already known, in which means are provided for safeguarding against explosion and preventing unauthorized access to the interior of the lamp. Such means commonly include a device for interrupting the current on the breakage or removal of the globe, or on the lamp being taken out, one terminal of the source of current being joined to a contact in the interior of the casing and the other to the lamp socket.

According to the invention metal member is provided between the contact in the casing and the end contact of the lamp, normally joining these contacts but not directly connected to the source of current; Upon the safety device operating this member is jerked forward by a spring and is locked in the forward position. It is then impossible to press it again into contact with the contact in the casing and moreover it makes this contact inaccessible.

Three formsof construction are illustrated in the accompanying drawings. The first form is shown in elevation in Figure 1, and in cross section on line T]Z of Fig. 1 in Fig. 2. Fig. 3 is a, cross section of a second form. Figs. 1 and 5 are sections on the line ll-TT of F ig. 3, Fig. 4 being a View loo-lo ing toward the point of the incandescent lamp, and Fig. 5 a view looking from the point of the lamp. Fig. 6 shows a third form of construction also in cross section.

Before the details of the different forms of construction are referred to, those parts may be described which are the same in all the constructions. v The lamp is supposed in all the examples to. be portable and has a metal casing A. This contains a source of current which may for example be two series connected voltaic cells B or a secondary battery. @nepole of the source ofcurrcnt is joined to the contact C which is mounted in the interior of the casing but.insulatedtherefrom. The other pole of the source is connected to the metal casing A through a fuse D." One wall of this casing, for example the front wall, has a circular opening in the middle of which the insulated contact C isarranged and which is surrounded by a circularflange E. In this flange engages a ring F having two pins F which engage in a circumferential slot on the inner surface of the flange E. Branching from this circumferential slot are two slots parallel to the axis of the ope ing extending to the front edge of the flange which allow the insertion and removal of the ring F with its pins F. In this way the ring F is secured in the flange E by so-called bayonet joint which, however, may be replaced by any other suitable connection. Over the edge F of the ring F engages a' covering ring G which inits turnas is disclosed in the U. S. A. Patents Nos. 1,022,072 and 1,022,073, both of Apr. 2, 1912,'and No. 1,025,394: of May 7, 1912, all granted to Gottschalck-forms a bayonet connection with projections A on the casing A1. The covering ring G is so formed and arrangedalso in known manner that it can only be removed after the casing is opened. Thus the insertion or removal of the ring F and of the parts secured to it and supported by it are only possible after removal of the covering ring G. The ring descent lamp is inserted in a metal casing J fastened to the insulating disk K. This lattcr carries also a reflector L which is conductively connected with the casing J together with a cap M which mustbe insulated from the casing J. There is also secured upon the insulating disk K a thin metal disk N having springy lugs N which must be conductively connected to the easmg J. The cap M covers the socket of the incandescent lamp and normally, 2'. a. in the position shown, forms a conductive connection between the contact C 1n the interior of the casing and the end contact I of the in- -candescent lamp I. Between the edge of the cap M or the insulating disk .K and an in j Sula-ting plate 0' which covers the-opening 2- in the casing within the circularflange E is; arranged a spring P.

' opening in the plate 0 for the passage of the closed end of the cap M. The interior. of the ring F has a screw thread on .a'. part vof its length and in this is inserted a'ring '53. Between this latter and the flange of the globe If is introduced a ring Q} of soft rubber. The interior of ring Q, is smooth near the insulating disk 0 but at the other end is provided with notches Q The projections N of'the metal disk N rest against the inner surface of the ring Q. The re flectoi L abuts against theshoulder H on the globe H.

following manner: Normally all the parts are in the position shown in Fig. 2. The

- current from the source B therefore takes longer held back by the shoulder H the the following path: battery B, fuse D, casing A, flange I), ring F, ring Q, projections N disk N, casing 'J, screw thread I, filament I end contact I cap M, contact C, battery B. If the globe H receives a jar or blow which may be dangerous to the incandescent lamp I it breaks off atv-the shoul the disk I in the notches of ring Q to movethe members back into the position shown so as to close the circuit again. It is equally impossible to close the ci'rcuitgby rotating the incandescent lamp I for if it is screwed down' after the breaking of the globe H it never reaches contact C.

By making the shoulder H? in the. globe H sufficiently broad it is possible to insure that the globe shall be broken by any shock or blow whichcould endanger the incandes- There is a central (Fig. 4C).. its-metal coating H bears on the turned The construction described operates in the cent lamp I. But then the globe H would be itself too delicate that is to say it wouldv bon like metal lining II which may bmproduced by burning, by electro-deposit on"or otherwise. The lining H in the first'lpl-ace completely covers the outer side-of theitlanjge H and the inner side of a notch I-I yetto In this case. the globe H itself is brought intothe circuit and for this purpose is provided with a ribbe described. From the latter it is carried up. a little way on the inner side ofthe globe toward its rounded portion, then forms a nearly closed ring and from this is continued tothe inner side of the flange H and" there also forms a nearly closed ring The-inner side of flange II with The reflector L is mounted and insulated upon the front side of the outer insulating plate K and surrounds the incandescent lamp I to a certain height. In the notch H- of the globe II is a pin F which is inserted in ring F and engages also in a corresponding notch in the insulating plates K. Thus the various parts can only be put to gether in one particular relative position of the insulating disksK with the members secured to them and of the globe II. purpose of thus fixing the mutual position is that the current passing from the ring F to the metal lining H on the outer side of the flange 11* must pass through the whole length of the lining H before it reaches the ro'ections It uoon the rin It. Normally P l l b the current takes the following path: Battery B, fuse D, casing A, ring F, metal lining H of the globe H, through all its through it again by introducing -a wire through a hole or gap in the shattered globe H putting one end 'of it,on the casing A or the ring F and the other onthe casingJ; That, however-, is prevented by the special formation of the reflectorL. This makes the casing J Or the screw thread I accessible only on the removal of the incandescent The 4 lamp I. Such removal, however, breaks,the contact between the end contact I and the cap M and it is therefore impossible by these means to get current through the incandescent lamp. Now it might occur to some one to prevent breaking of-the contact between end contact I and the cap M by screwing out the incandescent. lamp and inserting a small pi e'ctyof metal in the cap M. Even then, however, it is not possible to get current to pass on re-insert'ing the lamp 1, for the piece of metal would either im-,

mediately short-circuit between the cap M and the casing J which is specially lengthened for this purpose so that fuse I) would blow, or such short-circuit would be produced on the screwing in of the incan descent lamp since its conical end would press the piece of metal to one side so as to bring it against the casing J. After the lamp I is screwed'out it is certainly possible to establish connection 0, 9. through a wire between the casing A or the ring F on the one hand and the cap M or the contact O on the other hand. That, however, would short-circuit the source of current and immediately blow the fuse D in the interior of the casing so that no spark could be produced outside which might ignite combustible gas. Finally, if after the globe H has been broken the fragments of its flange H are removed which may yet be within the ring-F, the spring P expands and presses out the insulating plate K with the members secured upon it and the springy projections N and disk N engage in the notches of ring Q, as described in connection with the first form of construction.

, The third form of construction (F ig. (l) differs from the second in the fact that the spring P here presses only on a special insulating disk C whichcarrics the cap M to which is secured the disk N with its sprin afy projections N All the remaining parts in this construction are fixed. In this case the spring P expands if the incandescent lamp 1 is merely screwed out. If this is done the disk N moves forward and its projections N engage in the notches of the ring Q. Itis therefore impossible after the lamp has been screwed out to press back the cap M far enough to permit it coming in contact with contact C. Finally in the form of con-' struction according to Fig, (3 the ring Q. is provided vitha flange Q upon which the spring P abuts. This arrangement, which may be adopted in the other constructions, has the purpose of enabling all the parts to be reincved or replaced simultaneously with the ring F. I

The invention is not restricted to lamps of the type described in the introduction. For example the rings F, G may be secured in other manner than that illustrated.

Having now particularly described and ascertained the nature of our said invention and in what manner the same to be performed, we declare that what we claim is 1. In an electric safety lamp, the combination of a casing, a source of current therein, a fixed contact within said casing and joined to one pole of said source of current, a metal ring to receive a lamp and joined to the other pole of said source of current, a movable metal member within said ring and normally touching said mntact, a lamp having two terminals, one terminal being in contact with said ring and the other witlrsaid metal member, means tending to press said member out of connecting position, and means adapted to lock said member, when brought out of connecting position.

v '2. In an electric safety lamp, the combination of a casing, a source of current therein, a fixed contact within said casing and joined to one pole of said source of current, a metal ring to receive a lamp and joined to the other pole of said source of current, a movable metal member within said ring and normally touching said contact, a lamp having a circumferential and an end contact, the former being in contact with said ring and the latter with said metal member, means tending to press said member out of connecting position, and means adapted to lock said member, when brought out of connecting position.

3. In an electric safety lamp the combination with acasing of a source of current therein, a contact joined to said source of current, a lamp mounted in said casing, a terminal thereon, a metal member interposed between said terminal and said contact and normally joining the same, means tending to press forward said metal member so as to break contact, means for locking said member when thus pressed forward, and a lamp globe surrounding said lamp and normally retaining said metal member in position to establish contact.

4. in an electric safety lamp, the combination of a casing, a source of current therein, a fixed contact within said casing and joined to one pole of said source of current, a

metal ring to receive a lamp and joined to the other pole of said source of current a movable metal member within said ring and normally touching said contact, a lamp haring two terminals, one terminal being in contact with said ring and the other with said metal member, means tending to press said member'outof connecting position, means adapted to lock said member, when brought out of connect ng position, a globe covering the lamp and independent in ans iior breaking' the lamp circuit upon rupture of the globe.

5. In an electric safety lamp the combination of a casing containing a source of current, a mounting to receive a lamp, a

mally tending to press said caporward'.

7. In an electric safety lamp, the combination of a casing containing a source of current, a boss thereon, a ring, a removable fastening securing said ring in said boss, a lamp mounting supported in said ring, a

' notched member supported in' saidring, a

contact within said boss, a cap covering said contact, springy arms attached to said cap adapted to'engage said notches and means tending topress forward said cap.

8,111 an electric safetydamp, the combi-' nation ofa casing containing a source of current, a, boss thereon, a ring, a removable fastening securing said ring in said boss, a lamp mounting supported in" said ring, a globe covering said mounting and supported in said ring, a notched member supported in said ring, a contact within said boss, a cap covering said contact, springy arms attached to said cap adapted to engage said notches and means tending topress forward said cap.

9. In an electric safety lamp, a casing, a boss on said casing, a contact within said boss, a notched member within said boss, a

i disk having springy projections adapted to engage said notches, a lamp mounting attached to said casing, a metal cap interposed between said lamp mounting and said contact,"a-globe having a shoulder around said mounting, a reflector attached to said mounting and abutting upon said shoulder, and means for pressing forward said cap,

disk and mounting so as to press said re flector upon said shoulder.

10. An electric safety lamp comprising a casing, a source of current therein, a boss upon said casing, a notched member within said boss connected to one pole of said source, a contact within saidboss connected to theoppositepole, said source of current being insulated from said casing, a cap covering said contact, a disk supporting a lamp socket and carrying springy projections adapted to engage said notched member, and means tending to press forward said cap and said disk.

11. An electric safety lamp comprising a casing, a source of current therein, a contact joined to one pole of said source, a cap covering and normally touching said contact, means normally pressing forward said cap and means for locking said cap when pressed forward, a globe normally preventing said forward movement, a lamp socket within said globe, a metallic ribbon upon said globe, and connections between said lhmp socket, metallic ribbon and the other pole of the source.

In witness whereof, we have hereunto signed our names this 25 day of Nov. 1912, in the presence of two subscribing Witnesses. I

EMIL GOTTSOHALCK. LOTHAR WERNER. AUGUST GAST.

W i tnesses lVoLDnMAn HAUr'r, IIENRY HAsrnn. 

